1. Field of the Invention
Aspects of the present invention relate to an apparatus and method to discriminate an optical disc type, and more particularly, to an apparatus and method to discriminate an optical optical discs in an optical disc system to record and/or to reproduce data to and/or from an optical disc as a recording medium.
2. Description of the Related Art
As the field of audio/video storage media has been developed, optical discs capable of recording and reproducing high-quality image data and high-quality sound data have been developed and commercialized. Data is generally recorded onto and reproduced from these optical discs, which are types of storage media, through the use of a laser beam. Conventionally, low density optical discs, such as compact discs (CD) or digital versatile discs (DVD), have been widely used. However, in order to overcome the relatively low storage capacity limit of these low density optical discs, companies have developed high density optical discs capable of storing a relatively large amount of data. These high density optical discs, such as a Blu-ray disc-recordable (BD-R), a Blu-ray disc-rewritable (BD-RW) or a high density DVD (HD-DVD), have been recently developed and come into widespread use, and can store for example, at least several dozens of gigabytes of data
A low density optical disc is different from a high density optical disc in various ways. The low density optical disc uses a laser beam to record and reproduce data which has a larger wavelength than the laser beam used with the high density optical disc, the low density optical disc has a smaller storage capacity than the high density optical disc, the low density optical disc has a larger track pitch than the high density optical disc, and the low density optical disc has a thicker substrate thickness than the high density optical disc. In recently released optical disc systems, a variety of types of optical discs are used in a single apparatus. Accordingly, the type of optical disc mounted in an optical disc drive must be discriminated before recording data to and reproducing data from the optical disc.
Various methods to discriminate an optical disc type have been suggested. For example, Korean Patent Publication No. 1998-014340 discloses a method for discriminating an optical disc type. In the method for discriminating the optical disc type disclosed in the above publication, an apparatus, which reproduces data from optical discs having different substrate thicknesses, includes a sensor that has a light emitting device which emits a light signal and a plurality of light receiving devices which receives light signals reflected from the optical discs. The light receiving signals are different from one another due to a difference among the thicknesses of the optical discs. The light signals received by the light receiving devices of the sensor are analyzed to discriminate an optical disc type.
However, the above-mentioned method for discriminating the optical disc type can discriminate optical discs having different substrate thicknesses, but has difficulty discriminating between an HD-DVD and a DVD, since the substrate thickness (i.e., the distance between a surface layer and a recording layer) of the HD-DVD is similar to that of the DVD.